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Marchal, R., Mothe, F., Denaud, L. E., Thibaut, B., & Bleron, L. (2009). Cutting forces in wood machining – Basics and applications in industrial processes. A review COST Action E35 2004-2008: Wood machining – micromechanics and fracture. Holzforschung, 63(2), 157–167.
Abstract: The data available in the literature concerning wood cutting forces permits to build models or to simulate the main wood machining processes ( milling, sawing, peeling, etc.). This approach contributes to a better understanding of formation of wood surfaces and chips and the data may be helpful to optimise cutting geometry, reduce tool wear, improve tool material, and to size tool-machines. The models may also be useful for industrial application in two ways: ( 1) providing data to optimise the settings for a given operation ( batch approach), and ( 2) building predictive models that could be the basis of an online control system for the machining processes ( interactive approach). A prerequisite for this is that numerous machining tests on different wood materials are performed based on experiences with different kind of tools and experimental devices. With a focus on potential industrial applications, the emphasis of this review was on the wood peeling process, which is a very demanding special case of wood cutting. Although not so many industrial machines are equipped with expensive force sensors, there is a lot of high quality information available about cutting forces which may be useful to improve the scientific or technological knowledge in wood machining. Alternative parameters, such as vibration or sound measurements, appear to be promising substitutes in the praxis, particularly to feed online control systems of any wood cutting process.
Keywords: cutting forces; online control; peeling process; physico-mechanical model; sound; vibrations; wood industry; wood machining
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Malhi, Y., Aragao, L. E. O. C., Metcalfe, D. B., Paiva, R., Quesada, C. A., Almeida, S., et al. (2009). Comprehensive assessment of carbon productivity, allocation and storage in three Amazonian forests. Glob. Change Biol., 15(5), 1255–1274.
Abstract: The allocation and cycling of carbon (C) within forests is an important component of the biospheric C cycle, but is particularly understudied within tropical forests. We synthesise reported and unpublished results from three lowland rainforest sites in Amazonia (in the regions of Manaus, Tapajos and Caxiuana), all major sites of the Large-Scale Biosphere-Atmosphere Programme (LBA). We attempt a comprehensive synthesis of the C stocks, nutrient status and, particularly, the allocation and internal C dynamics of all three sites. The calculated net primary productivities (NPP) are 10.1 +/- 1.4 Mg C ha(-1) yr(-1) (Manaus), 14.4 +/- 1.3 Mg C ha(-1) yr(-1) (Tapajos) and 10.0 +/- 1.2 Mg C ha(-1) yr(-1) (Caxiuana). All errors bars report standard errors. Soil and leaf nutrient analyses indicate that Tapajos has significantly more plant-available phosphorus and calcium. Autotrophic respiration at all three sites (14.9-21.4 Mg C ha yr(-1)) is more challenging to measure, with the largest component and greatest source of uncertainty being leaf dark respiration. Comparison of measured soil respiration with that predicted from C cycling measurements provides an independent constraint. It shows general good agreement at all three sites, with perhaps some evidence for measured soil respiration being less than expected. Twenty to thirty percent of fixed C is allocated belowground. Comparison of gross primary productivity (GPP), derived from ecosystem flux measurements with that derived from component studies (NPP plus autotrophic respiration) provides an additional crosscheck. The two approaches are in good agreement, giving increased confidence in both approaches to estimating GPP. The ecosystem carbon-use efficiency (CUEs), the ratio of NPP to GPP, is similar at Manaus (0.34 +/- 0.10) and Caxiuana (0.32 +/- 0.07), but may be higher at Tapajos (0.49 +/- 0.16), although the difference is not significant. Old growth or infertile tropical forests may have low CUE compared with recently disturbed and/or fertile forests.
Keywords: allocation; Amazonia; carbon; growth; litterfall; productivity; respiration; roots; soil; tropical forest
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Male, P. J. G., Loiseau, A., Estoup, A., Quilichini, A., & Orivel, J. (2010). Characterization of polymorphic microsatellite loci in the neotropical plant-ant Allomerus decemarticulatus (Formicidae: Myrmicinae) and multiplexing with other microsatellites from the ant subfamily Myrmicinae. Eur. J. Entomol., 107(4), 673–675.
Abstract: Five polymorphic microsatellite loci of the arboreal ant Allomerus decemarticulatus (Myrmicinae) were isolated and characterized. The amplification and polymorphism of seven additional microsatellite loci, previously developed for the ant species A. octoarticulatus and Wasmannia auropunctata, were also tested and the amplification conditions necessary for genotyping the complete set of 12 multiplexed markers in A. decemarticulatus determined. The number of alleles per locus ranged from three to 15 and observed heterozygosity varied front 0.09 to 0.95. Cross-species amplification of these loci was also successfully achieved in additional species of the same ant subfamily, Myrmicinae. This set of microsatellite markers will be used in studies on the mating system and population genetic structure of Myrmicinae in general and A. decemarticulatus in particular.
Keywords: Hymenoptera; Formicidae; Myrmicinae; Allomerus; ant-plant mutualism; microsatellites; plant-ant
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Cohen, M. C. L., Behling, H., Lara, R. J., Smith, C. B., Matos, H. R. S., & Vedel, V. (2009). Impact of sea-level and climatic changes on the Amazon coastal wetlands during the late Holocene. Veg. Hist. Archaeobot., 18(6), 425–439.
Abstract: Wetland dynamics in northern Brazil during the Holocene were studied by pollen analysis and AMS radiocarbon dating of three cores. Near the Amazon mouth region, covered mainly by primary Amazon coastal forest and herbaceous vegetation, the pollen record indicates the dominance of mangroves between 4800 and 1100 cal yr B.P. A contraction of the mangrove area and an expansion of herbaceous and fern vegetation occurred between 1100 and 750 cal yr B.P. The period between 750 and 200 cal yr B.P. is characterized by an expansion of mangrove and a decrease in herbaceous and fern vegetation. This trend continued until the present. On Atalaia Island, the sediment core indicates a period with poor pollen preservation between 830 and 630 cal yr B.P. Between 630 and 330 cal yr B.P., mangroves expanded. Later, up to 45 cal yr B.P., the mangrove area decreased and the herbaceous vegetation expanded. During the last hundred years, the relative sea-level rise most probably favored the mangrove expansion as far as the topographically highest sector on this island, while the herbaceous vegetation decreased. The pollen data from Agua Preta Lake indicate dry conditions, as reflected by the poor pollen preservation between 390 and 240 cal yr B.P. Between 240 and 60 cal yr B.P., restinga and Amazon coastal forest with palms dominated this region. For the last 120 years, the record indicates an expansion of the mangrove area. However, recent confinement of mangrove development to the topographically highest area, and the loss of mangrove areas on the lowest surfaces have led to a net loss of mangrove coverage during the last decades.
Keywords: Mangrove; Marajo Island; Pollen analysis; Sea-level
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Li, M. C., Royer, M., Stien, D., Lecante, A., & Roos, C. (2008). Inhibitive effect of sodium eperuate on zinc corrosion in alkaline solutions. Corrosion Sci., 50(7), 1975–1981.
Abstract: The effect of sodium eperuate prepared from Wallaba (Eperua falcata Aubl) extract on zinc corrosion was investigated in alkaline solutions with chloride ions (i.e., simulated concrete pore solutions) by using electrochemical techniques. Sodium eperuate inhibits the corrosion of zinc in 0.1 M NaCl solutions with pH 9.6. As its concentration increases to 1 g/L, the inhibition efficiency reaches approximately 92%. In alkaline solutions with pH 12.6, sodium eperuate has no adverse effect on passivity of zinc, and retards the chloride attack. These suggest that sodium eperuate is an effective inhibitor for the protection of zinc in alkaline environments. (c) 2008 Elsevier Ltd. All rights reserved.
Keywords: zinc; concrete; EIS; alkaline corrosion; passivity
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Leroy, C., Cereghino, R., Camas, J. F., Pelozuelo, L., Dejean, A., & Corbara, B. (2010). Several aspects of the life of vascular epiphytes. Biofutur, 315, 38–41.
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Leroy, C., Jauneau, A., Quilichini, A., Dejean, A., & Orivel, J. (2008). Comparison between the anatomical and morphological structure of leaf blades and foliar domatia in the ant-plant Hirtella physophora (Chrysobalanaceae). Ann. Bot., 101(4), 501–507.
Abstract: Background and Aims Myrmecophytes, or ant-plants, are characterized by their ability to shelter colonies of some ant species in hollow structures, or ant-domatia, that are often formed by hypertrophy of the internal tissue at specific locations (i.e. trunk, branches, thorns and leaf pouches). In Hirtella physophora (Chrysobalanaceae), the focal species of this study, the ant-domatia consist of leaf pouches formed when the leaf rolls over onto itself to create two spheres at the base of the blade. Methods The morphological and anatomical changes through which foliar ant-domatia developed from the laminas are studied for the first time by using fresh and fixed mature leaves from the same H. physophora individuals. Key results Ant-domatia were characterized by larger extra-floral nectaries, longer stomatal apertures and lower stomatal density. The anatomical structure of the domatia differed in the parenchymatous tissue where palisade and spongy parenchyma were indistinct; chloroplast density was lower and lignified sclerenchymal fibres were more numerous compared with the lamina. In addition, the domatia were thicker than the lamina, largely because the parenchymatous and epidermal cells were enlarged. Conclusion Herein, the morphological and anatomical changes that permit foliar ant-domatia to be defined as a specialized leaf structure are highlighted. Similarities as well as structural modifications in the foliar ant-domatia compared with the lamina are discussed from botanical, functional and mutualistic points of view. These results are also important to understanding the reciprocal evolutionary changes in traits and, thus, the coevolutionary processes occurring in insect-plant mutualisms.
Keywords: anatomy; ant-plant mutualism; Chrysobalanaceae; extra-floral nectaries; French Guiana; Hirtella physophora; secondary domatia
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Leroy, C., Corbara, B., Dejean, A., & Cereghino, R. (2009). Ants mediate foliar structure and nitrogen acquisition in a tank-bromeliad. New Phytol., 183(4), 1124–1133.
Abstract: Aechmea mertensii is a tank-bromeliad that roots on ant-gardens initiated by the ants Camponotus femoratus and Pachycondyla goeldii. Its leaves form compartments acting as phytotelmata that hold rainwater and provide habitats for invertebrates. In this article, we aimed to determine whether the association with either C. femoratus or P. goeldii influenced the vegetative traits of A. mertensii, invertebrate diversity and nutrient assimilation by the leaves. Transmitted light, vegetative traits and phytotelmata contents were compared between the two A. mertensii ant-gardens. Camponotus femoratus colonized partially shaded areas, whereas P. goeldii colonized exposed areas. The bromeliads' rosettes had a large canopy (C. femoratus ant-gardens), or were smaller and amphora shaped (P. goeldii ant-gardens). There were significant differences in leaf anatomy, as shaded leaves were thicker than exposed leaves. The mean volumes of water, fine particulate organic matter and detritus in C. femoratus-associated bromeliads were three to five times higher than in P. goeldii-associated bromeliads. Moreover, the highest invertebrate diversity and leaf delta N-15 values were found in C. femoratus-associated bromeliads. This study enhances our understanding of the dynamics of biodiversity, and shows how ant-plant interactions can have trophic consequences and thus influence the architecture of the interacting plant via a complex feedback loop.
Keywords: Aechmea mertensii; antgardens; Camponotus femoratus; foliar structure; delta N-15; Pachycondyla goeldii; phytotelmata contents
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Leroy, C., Jauneau, A., Quilichini, A., Dejean, A., & Orivel, J. (2010). Comparative Structure and Ontogeny of the Foliar Domatia in Three Neotropical Myrmecophytes. Am. J. Bot., 97(4), 557–565.
Abstract: The origin and timing of the appearance of leaf domatia during the ontogeny of plants are important evolutionary traits driving the maintenance of ant-plant associations. In this study conducted in French Guiana on Hirtella physophora, Maieta guianensis, and Tococa guianensis, we focused on the formation and development of leaf domatia having different morphological origins. We modeled the timing of the onset of these domatia, then compared their morpho-anatomical structure. Although the ontogenetic development of the domatia differed between species, they developed very early in the plant's ontogeny so that we did not note differences in the timing of the onset of these domatia. For H. physophora seedlings, a transitional leaf forms before the appearance of fully developed domatia, whereas in M. guianensis and T. guianensis the domatia forms abruptly without transitional leaves. Moreover, in all cases, the morpho-anatomical structure of the domatia differed considerably from the lamina. All three species had similar morpho-anatomical characteristics for the domatia, indicating a convergence in their structural and functional characteristics. This convergence between taxonomically distant plant species bearing domatia having different morphological origins could be interpreted as a product of the plant's evolution toward the morphology and anatomy most likely to maximize ant recruitment and long-term residence.
Keywords: anatomy; ant-plant mutualism; Chrysobalanaceae; domatia; French Guiana; Hirtella physophora; Maieta guianensis; Melastomataceae; myrmecophyte; ontogeny; Tococa guianensis
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Ruiz-Gonzalez, M. X., Male, P. J. G., Leroy, C., Dejean, A., Gryta, H., Jargeat, P., et al. (2011). Specific, non-nutritional association between an ascomycete fungus and Allomerus plant-ants. Biol. Lett., 7(3), 475–479.
Abstract: Ant-fungus associations are well known from attine ants, whose nutrition is based on a symbiosis with basidiomycete fungi. Otherwise, only a few non-nutritional ant-fungus associations have been recorded to date. Here we focus on one of these associations involving Allomerus plant-ants that build galleried structures on their myrmecophytic hosts in order to ambush prey. We show that this association is not opportunistic because the ants select from a monophyletic group of closely related fungal haplotypes of an ascomycete species from the order Chaetothyriales that consistently grows on and has been isolated from the galleries. Both the ants' behaviour and an analysis of the genetic population structure of the ants and the fungus argue for host specificity in this interaction. The ants' behaviour reveals a major investment in manipulating, growing and cleaning the fungus. A molecular analysis of the fungus demonstrates the widespread occurrence of one haplotype and many other haplotypes with a lower occurrence, as well as significant variation in the presence of these fungal haplotypes between areas and ant species. Altogether, these results suggest that such an interaction might represent an as-yet undescribed type of specific association between ants and fungus in which the ants cultivate fungal mycelia to strengthen their hunting galleries.
Keywords: ant-fungus association; Cordia nodosa; Chaetothyriales; Hirtella physophora; myrmecophyte; population structure
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